Internal combustion engines an oil lubrication system to reduce or eliminate friction between internal moving components. These oil lubrication systems typically incorporate an oil filter that continuously filters the circulating engine oil. The filtration process extends the useful life of the lubricating oil.
The typical oil lubrication system of the modern internal combustion engine includes an oil fill hole and an oil drain hole. To measure the oil level in the engine, conventional fluid level indicating systems have generally included a level indicating embodied as a weighted wire, a rod, or a thin, flexible blade. The wire, rod, or blade is graduated at one end for indicating depth. The level indicating is allowed to pass through a tube and into the oil of the engine's crankcase sump so as to provide a direct oil level reading within the engine. Known fluid level indicating systems have typically used externally mounted tubes that sometimes extend through a sidewall of a cylinder block.
The indicating tubes of known fluid level indicating systems have certain durability requirements that require them to be formed from steel. In addition, the interior bore must be sufficiently smooth so as to permit the removable level indicating to be readily withdrawn from the indicating tube and re-inserted into the indicating tube without restriction.
Ease of removal and reinsertion of the level indicating is one important consideration in the design and execution of a fluid level indicating system. Another important consideration is the placement of the level indicating tube as the gripping portion of the level indicating must be reasonably accessible to the vehicle operator. An additional aspect of the fluid level indicating system is that it be relatively inexpensive to manufacture and install. A final aspect of the fluid level indicating system is that it must be durable.
Historically, it has been virtually impossible to satisfy the objectives of ease of removal and reinsertion, convenient placement for easy access, low cost for manufacturing and assembly, and high durability. Perhaps the most difficult of these goals to achieve is the challenge created by engine packaging. Given the trend of placing a greater number of engine components into a more restricted space, practical accessibility of the level indicating is often compromised by the fact that level indicating tubes occupy space which is almost always at a premium in modern automotive vehicle engine compartments. Further complicating the situation for designers is the fact that it is common in the automotive industry to use the same engine between several body types and thus between different engine compartment configurations. Often each body type requires its own oil indicating tube having specific lengths and bends so as to accommodate variations in the engine and the engine compartment.
A conventional fluid level indicating system is illustrated in FIG. 1. As illustrated in this figure, an internal combustion engine 10 is shown in an elevated side view. The internal combustion engine 10 includes an engine block 12 having an exhaust manifold 14. A single, pre-formed oil indicating tube 16 is conventionally attached to the engine block 12 at an attachment point 18. A dipstick 20 is shown inserted into the indicating tube 16. The indicating tube 16 has the attachment point 18 and may be secondarily attached to the engine block 12 at an additional point (not illustrated).
As in so many areas of vehicle technology there is always room for improvements related to the design of an engine lubricating system for use in an conjunction with internal combustion engine. Particularly, it would be advantageous to provide a fluid level indicating system that may be universally adapted for use in a variety of different vehicles while providing accessibility and durability coupled with relatively low production and assembly costs.